Reduction transmission for marine machinery



' y 2 1965 s. "r. LUNDSTROM 3,196,714

REDUCTION TRANSMISSION FOR MARINE MACHINERY Filed May 13. 1964 2 Sheets-Sheet 1 IN V EN TOR.

Jtz' fiwzemzumzsirsm July 27, 1965 s. 1'. LUNDSTRGM REDUCTION TRANSMISSION FOR MARINE MACHINERY Filed May 13. 1964 2 Sheets-Sheet 2 P INVENTOR. v (551 575561 Z ZZ7Z6ZZ72 7R1 BY i United States Patent 3,196,714 REDUCTHON TRANSMISSEON FOR MARINE MACHINERY Stig Torsten Lnndstrdm, Nacka, Sweden, assignor to Stal- Laval Turbin Alrtieholag, Finspong, Sweden, a Swedish corporation Filed May 13, 1964, Ser. No. 366,986 (Ilairns priority, application Sweden, May 13, 1963, 5,229/63 1 Claim. (Cl. 74665) The present invention relates to a reduction transmission and particularly to a type suitable for marine purposes. Such transmission includes two turbines, one of which is a high pressure turbine and the other a low pressure turbine, the apparatus to be described being employed for the reduction in two steps of the turbine rotational speed to the rotational speed of the propeller shaft.

The invention is principally characterized by the arrangement of the first stage as epicyclic gearing with an input shaft coupled to one of the turbine shafts and extended through a hollow output shaft from the epicyclic gearing, this output shaft carrying between the epicyclic gearing and the turbine a gear pinion forming part of the second stage and meshed With a gear wheel fitted on the propeller shaft. The use of epicyclic gearing as above described makes the overall dimensions of the apparatus relatively small and also of relatively light weight and it is thus possible to combine the reduction gearing with reversing arrangements. According to the present invention, the epicyclic gears are placed outside the second reduction stage and as a result the base plate for the machinery will be small which means that the bed in the ship can be small, this tending to simplify the installation and the alignment of the machinery. Another advantage is that movements of the ships hull will be transferred to the machinery to a lesser extent.

With these objects and other objects to be hereinafter set forth in view, I have devised the arrangement of parts to be described and more particularly pointed out in the claim appended hereto.

In the accompanying drawings, wherein an illustrative embodiment of the invention is disclosed,

FIG. 1 shows the apparatus according to the invention installed for marine purposes and as viewed in plan or from above and in part in horizontal section, the view being taken substantially on the line II of FIG. 2, looking in the direction of the arrows;

FIG. 2 shows the gearing drawn in another scale and viewed from the end, and

FIG. 3 is a horizontal sectional view, taken substantially on the line III-III in FIG. 2, looking in the direction of the arrows.

Referring to the drawings, 1 indicates a high-pressure turbine, and 2 indicates a low-pressure turbine provided with the condenser 3. At 4 and 5 are shown respectively the turbine shafts. At 6 is indicated a propeller shaft. The reduction of the turbine speed to the propeller shaft occurs in two stages. Since the reduction in speed occurs in the same manner for the two stages or for both turbines, the following description will be confined to the high-pressure turbine reduction.

The first stage comprises an epicyclic gearing 7 which is arranged on that side of the second-stage gearing that faces away from the turbine 1. The second stage includes a gear wheel 9 which is fixed on the propeller shaft 8, and a gear pinion 1t) driven by an output shaft 11 from the epicyclic gearing '7. As seen in FIG. 1, the shaft 11 is hollow and has an extension 12 from shaft 5 passing through the shaft 11 to the epicyclic gearing, which per se is of a known type and hence is not described herein in detail. The gearing is enclosed in a casing 13. The thrust bearing for the propeller shaft is indicated at 14.

As will be seen in FIG. 2, the axes 15, 16 and 17 of the gear pinions and the propeller shaft lie in the same horizontal plane. As will be seen in FIG. 2, the casing 13 is symmetrically arranged about a plane represented by the line 1818 in FIG. 2.

The casing 13 rests on four supports, shown at 19, 20, 21 and 22 which it will be seen are located at the center of each vertical side of the casing.

The epicyclio gearing sets shown respectively at 7 and 7a, may be arranged so that the direction of rotation of the propeller shaft can be reversed.

Because of the arrangement of the shafts of the gears and pinions as well as the propeller shaft in the same horizontal plane and the location of the epicyclic gears laterally outside of the second stage, the gear casing will be nearly symmetrical, which permits the erection of the apparatus on four supports in the machine bed. This means that the tooth contact between the gears will not be affected by distortions of the hull of the ship. Location of the several shafts in the same plane also facilitates alignment and manufacture since it is easy to secure distances between centers and to secure parallelism. This is of great importance in connection with gearing. The symmetry of the casing prevents uneven temperature distribution and deformation.

Having thus described a single embodiment of the invention, it is obvious that the same is not to be restricted thereto, but is broad enough to cover all structures coming within the scope of the annexed claims.

What I claim is:

A reduction transmission for marine machinery comprising, a high pressure turbine and a low pressure turbine for the reduction in two steps of the turbine rotational speed to propeller shaft rotational speed, the first stage having epicyclic gearing having an input shaft coupled to one of the turbine driven shafts, a hollow output shaft extending from the epicyclic gearing, said input shaft extending through the hollow shaft, the hollow shaft being provided with a pinion located between the epicy-clic gearing and the turbine, said pinion forming a part of the second stage, and a gear wheel on the propeller shaft in mesh with said pinion, the axis of the pinions and the propeller shaft being located in the same horizontal plane with a casing enclosing and supporting the gearing and which casing is mainly symmetrical about a vertical plane passing longitudinally through the propeller shaft, said gear casing being of rectangular shape and erected on four supports placed one at the center of each side of the rectangle formed by the gear casing.

References Cited by the Examiner UNITED STATES PATENTS 2,708,416 5/55 Schmitter 74661 FOREIGN PATENTS 930,702 8/47 France.

DON A. WAITE, Primary Examiner. 

